The present invention relates to a television system comprising a television set (TV) having a display screen and speakers and a tuner for receiving conventional or “legacy” analogue data from which television channels can be generated, and a broadcast data receiver for receiving data transmitted via a digital data system and from which digital data television channels can be generated.
In due course the broadcasting of conventional analogue data television channels will be discontinued and wholly replaced by the use of digital data television channels.
In order to continue to use analogue TV equipment after the analogue data service is switched off, will require the provision of conversion devices that allow the conversion of the new digital data transmissions into a form which can be shown on conventional analogue equipment.
With the advent of digital terrestrial television, many governments, broadcast authorities and other radio frequency (RF) spectrum managing authorities are seeking to switch off the conventional analogue TV transmissions as soon as possible. Unfortunately, this will leave a very large number of previously installed “legacy” analogue TV equipment which, without updating, will be unable to operate. The inability to operate their TV apparatus will lead to frustration, considerable grievance and potential loss of viewers which is an important problem especially for those broadcasters which rely on advertising revenue.
One proposed solution is to provide a converter device that can receive and decode digitally transmitted data and remodulate the data in a form that can be received by the analogue equipment. However, the problem with this system is that data for each of the large number of channels which can be selected has to be processed simultaneously therefore leading to an unacceptable and/or uneconomical amount of processing power being required and computer memory and associated hardware being required and therefore costing more than the cost of replacing the “legacy” TV apparatus which it is intended to avoid.
However, it is equally clear that in order to allow the existing analogue equipment to be used with digital data broadcast TV services, a form of converter device is required. Existing Digital Broadcast Data Receivers (BDR's) for digital transmission systems are significantly more sophisticated than necessary for many consumers who in practice will simply want to watch the existing traditional or free to air “channels” (i.e., the user is not required to subscribe to the same) such as, in the UK, BBC1, BBC2, ITV, Ch.4 and Ch.5. Furthermore this type of BDR requires its own remote control to allow the user to change channels and set operating parameters and is more sophisticated and expensive than is required, especially when one considers that the Government or other authorities will probably wish to provide the BDR apparatus at a reduced cost.
A cost effective conversion device would only receive and decode one digital signal, but this signal must correspond to the channel that the analogue TV equipment, and hence the viewer, expects to watch following the viewer television channel selection. The problem is therefore how to discern what channel the TV equipment expects to receive and to provide the appropriate channel.
The aim of the invention is to utilize a digital to analogue converter but in a manner so as to seek to minimize the functionality required for the converter by detecting what channel the conventional or legacy TV receiver is tuned to and using that channel information to direct the converter device and BDR connected thereto to only process the RV channel that is required. Thus, the analogue TV equipment and the viewer should not be aware that the channel selected for viewing is generated from digital data rather than analogue data and hence is not affected by the removal of the analogue TV service.